Added c65cm stdlib as embedded into the c65gm exe so it's completely self contained, for easy distribution.

.gitignore

@@ -38,3 +38,5 @@ c65gm
 .env
 .local/
 opencode-config/package-lock.json
+internal/preproc/lib/
+.bun/

AGENTS.md

@@ -90,11 +90,13 @@ LABEL lib_mylib_skip
 ## Development Guidelines
 
 ### Environment Constraints
-**IMPORTANT**: The agent runs in a Docker container without access to compilers, testing tools, or external build systems. All compilation and testing must be performed by the user. The agent can only:
+**CRITICAL - NO GO TOOLS AVAILABLE**: The agent runs in a Docker container without access to compilers, testing tools, or external build systems. The container does NOT have Go installed (`go` command not found). All compilation and testing must be performed by the user. The agent can only:
 1. Read and analyze source code
 2. Make code changes
 3. Provide instructions for the user to compile and test
 
+**NEVER attempt to run `go build`, `go test`, or any Go commands** - they will fail with "go: not found".
+
 ### File Access Restrictions
 **CRITICAL**: The agent must only access normal project files within the current working directory. The agent must NEVER:
 1. Look at files outside the project directory (e.g., `/tmp/`, `/etc/`, `/home/`, etc.)
@@ -117,7 +119,7 @@ All file operations must be restricted to the project's source code and document
 4. Consider adding examples in `examples/` directory
 
 ### Testing and Rebuilding
-**IMPORTANT**: The agent cannot run tests or compile code. Provide these instructions to the user:
+**CRITICAL**: The agent cannot run tests or compile code. The container has no Go installation. Provide these instructions to the user:
 
 #### Testing:
 - Run all tests: `go test ./...`

build_c65gm.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+set -e
+
+# Copy lib directory to internal/preproc for embedding
+echo "Copying lib directory for embedding..."
+rm -rf internal/preproc/lib
+cp -r lib internal/preproc/
+
+# Build the binary
+echo "Building c65gm..."
+go build -o c65gm
+
+echo "Build complete: c65gm"

examples/shift_demo/cm.sh

@@ -2,9 +2,9 @@
 # Define filename as variable
 PROGNAME="shift_demo"
 # Only set C65LIBPATH if not already defined
-if [ -z "$C65LIBPATH" ]; then
-    export C65LIBPATH=$(readlink -f "../../lib")
-fi
+#if [ -z "$C65LIBPATH" ]; then
+#    export C65LIBPATH=$(readlink -f "../../lib")
+#fi
 # Compile - use absolute path to c65gm
 c65gm -in ${PROGNAME}.c65 -out ${PROGNAME}.s
 if [ $? -ne 0 ]; then

internal/preproc/embeddedlib.go

@@ -0,0 +1,38 @@
+package preproc
+
+import (
+	"embed"
+	"fmt"
+	"io/fs"
+	"strings"
+)
+
+//go:embed lib
+var embeddedLib embed.FS
+
+// embeddedLibPath returns the path within the embedded filesystem for a library include.
+// For example, "<c64start.c65>" becomes "lib/c64start.c65"
+func embeddedLibPath(spec string) (string, error) {
+	if !strings.HasPrefix(spec, "<") || !strings.HasSuffix(spec, ">") {
+		return "", fmt.Errorf("not an angle-bracket include: %s", spec)
+	}
+	
+	base := strings.TrimSpace(spec[1 : len(spec)-1])
+	return "lib/" + base, nil
+}
+
+// readEmbeddedFile reads a file from the embedded filesystem.
+func readEmbeddedFile(path string) ([]string, error) {
+	data, err := fs.ReadFile(embeddedLib, path)
+	if err != nil {
+		return nil, err
+	}
+	
+	// Split into lines, preserving empty lines
+	content := string(data)
+	lines := strings.Split(content, "\n")
+	
+	// If the file ends with newline, the last element will be empty
+	// This matches the behavior of strings.Split for disk files
+	return lines, nil
+}

internal/preproc/filereader.go

@@ -93,3 +93,16 @@ func (m *MockFileReader) ReadLines(includeSpec string, _ string) ([]string, stri
 	}
 	return lines, includeSpec, nil
 }
+
+// NewDefaultFileReader creates the appropriate FileReader based on C65LIBPATH environment variable.
+// If C65LIBPATH is set, returns a DiskFileReader for external library access.
+// If C65LIBPATH is not set, returns a HybridFileReader that uses embedded standard library.
+func NewDefaultFileReader() FileReader {
+	libPath := os.Getenv("C65LIBPATH")
+	if libPath != "" {
+		fmt.Printf("Using external library from: %s\n", libPath)
+		return NewDiskFileReader()
+	}
+	fmt.Println("Using embedded standard library")
+	return NewHybridFileReader()
+}

internal/preproc/filereader_test.go

@@ -3,6 +3,7 @@ package preproc
 import (
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 )
 
@@ -67,6 +68,51 @@ func TestDiskFileReader_ReadLines_LibraryWithoutEnv(t *testing.T) {
 	}
 }
 
+func TestHybridFileReader_ReadLines_LibraryIncludes(t *testing.T) {
+	origPath := os.Getenv("C65LIBPATH")
+	defer func() { _ = os.Setenv("C65LIBPATH", origPath) }()
+
+	// Test 1: With C65LIBPATH set, should use disk
+	libPath, _ := filepath.Abs("filereader_mocks/lib")
+	_ = os.Setenv("C65LIBPATH", libPath)
+	
+	reader1 := NewHybridFileReader()
+	lines1, path1, err1 := reader1.ReadLines("<test_lib.c65>", "")
+	if err1 != nil {
+		t.Errorf("HybridFileReader with C65LIBPATH should work: %v", err1)
+	}
+	if len(lines1) == 0 {
+		t.Error("expected lines from disk library")
+	}
+	if !strings.Contains(path1, "filereader_mocks") {
+		t.Errorf("expected disk path, got: %s", path1)
+	}
+
+	// Test 2: Without C65LIBPATH, should use embedded (will fail in test since no embedded mock)
+	_ = os.Setenv("C65LIBPATH", "")
+	reader2 := NewHybridFileReader()
+	_, _, err2 := reader2.ReadLines("<test_lib.c65>", "")
+	if err2 == nil {
+		// This is expected to fail in unit tests since we can't mock embedded FS easily
+		// In real usage, embedded library would be used
+		t.Log("Note: HybridFileReader without C65LIBPATH would use embedded library")
+	}
+}
+
+func TestHybridFileReader_ReadLines_RelativeIncludes(t *testing.T) {
+	reader := NewHybridFileReader()
+	
+	appDir, _ := filepath.Abs("filereader_mocks/app")
+	
+	lines, _, err := reader.ReadLines("test_app.c65", appDir)
+	if err != nil {
+		t.Errorf("HybridFileReader should handle relative includes: %v", err)
+	}
+	if len(lines) == 0 {
+		t.Error("expected lines from relative include")
+	}
+}
+
 func TestDiskFileReader_ReadLines_RelativeIncludes(t *testing.T) {
 	reader := NewDiskFileReader()
 

internal/preproc/hybridfilereader.go

@@ -0,0 +1,74 @@
+package preproc
+
+import (
+	"fmt"
+	"os"
+	"strings"
+)
+
+// HybridFileReader implements FileReader with support for both embedded
+// standard library (when C65LIBPATH is not set) and disk-based includes.
+type HybridFileReader struct {
+	diskReader    *DiskFileReader  // For relative includes & C65LIBPATH overrides
+	libPath       string           // From C65LIBPATH env var
+	usedEmbedded  bool             // Track if we've used embedded library
+	embeddedCache map[string][]string // Cache for embedded files
+}
+
+// NewHybridFileReader creates a new HybridFileReader.
+func NewHybridFileReader() *HybridFileReader {
+	return &HybridFileReader{
+		diskReader:    NewDiskFileReader(),
+		libPath:       os.Getenv("C65LIBPATH"),
+		embeddedCache: make(map[string][]string),
+	}
+}
+
+// ReadLines implements the FileReader interface.
+func (h *HybridFileReader) ReadLines(includeSpec string, currentDir string) ([]string, string, error) {
+	// Check if this is an angle-bracket include
+	if strings.HasPrefix(includeSpec, "<") && strings.HasSuffix(includeSpec, ">") {
+		// If C65LIBPATH is set, delegate to DiskFileReader
+		if h.libPath != "" {
+			return h.diskReader.ReadLines(includeSpec, currentDir)
+		}
+		
+		// Otherwise, use embedded library
+		if !h.usedEmbedded {
+			h.usedEmbedded = true
+			// Note: Library source message is printed by NewDefaultFileReader factory
+		}
+		
+		return h.readEmbeddedLibrary(includeSpec)
+	}
+	
+	// Relative includes always go to disk
+	return h.diskReader.ReadLines(includeSpec, currentDir)
+}
+
+// readEmbeddedLibrary reads a file from the embedded standard library.
+func (h *HybridFileReader) readEmbeddedLibrary(spec string) ([]string, string, error) {
+	// Convert angle-bracket spec to embedded path
+	embeddedPath, err := embeddedLibPath(spec)
+	if err != nil {
+		return nil, "", err
+	}
+	
+	// Check cache
+	if lines, ok := h.embeddedCache[embeddedPath]; ok {
+		// Return cached lines with virtual path for error messages
+		return lines, "<embedded>/" + strings.TrimPrefix(embeddedPath, "lib/"), nil
+	}
+	
+	// Read from embedded filesystem
+	lines, err := readEmbeddedFile(embeddedPath)
+	if err != nil {
+		return nil, "", fmt.Errorf("embedded library include not found: %s", spec)
+	}
+	
+	// Cache the result
+	h.embeddedCache[embeddedPath] = lines
+	
+	// Return with virtual path for error messages
+	return lines, "<embedded>/" + strings.TrimPrefix(embeddedPath, "lib/"), nil
+}

internal/preproc/preproc.go

@@ -38,7 +38,7 @@ func PreProcess(rootFilename string, reader ...FileReader) ([]Line, *Pragma, err
 	if len(reader) > 0 && reader[0] != nil {
 		r = reader[0]
 	} else {
-		r = NewDiskFileReader()
+		r = NewDefaultFileReader()
 	}
 	pp := newPreproc(r)
 	lines, err := pp.run(rootFilename)